I have a vague recollection that at one GP in the early 80's Ligier forgot to take a pressure gauge to one of the races so had to borrow one from one of the other teams to find out what their tyre pressures were.
At the 92 Canadian GP Andrea Moda had to borrow a Judd engine from Brabham because they'd failed to pay their engine bills. I think Roberto Moreno blew it up. Given that Brabham were strapped for cash and would also fold that season, it was incredibly generous of them.
I heard a nice story over the weekend from a friend of a friend who's the singer / guitarist for The Levellers. Jaques Villeneuve had a party in Barcelona 1999 a few days before the GP. Mark from The Levellers gets a phone call to come and play a gig, Jaques is apparently a big fan. All expenses paid, paddock tickets etc, and he says something like 'Hell yes!' The gig goes well, they're treated superbly, and party the night away with F1 drivers and all sorts of others. After the party winds down, a few of them are still drinking in a hotel room in the early hours including Mark, Jaques Villeneuve and Damon Hill. Damon is pissed, and blurts to everyone that he's not told anyone yet, but he's planning to retire at the end of the year. Which was a shock to everyone in the room. They way the story's told Damon was quite battered. Also Michael Schumacher was quite dull (didn't drink a drop) and was more concerned with pumping iron in his trailer, which was basically a mobile gym. And Mark introduced Jaques to Danni Minogue at the party, who soon got married.
Just picked this up from the "Test in F1" Facebook group, the first Jordan F1 car was to have been called the 911 but Porsche asked Eddie to change the name and gave him a car with the same number as sweetener. Here's John Watson test driving the car:
Didn't know but that's kind of ironic considering the Porsche 911 was supposed to be called "901" before Peugeot legally prevented Porsche calling it such as the "0" middle-digit is a Peugeot trademark.